This project seeks to: 1. To define the epidemiologic, behavioral and morphologic characteristics of human malignant neoplasms known or suspected of being caused by carcinogens in the environment. 2. To provide pathology support for epidemiologists of the NCI, NIOSH, CDC and other agencies and institutions. 3. To provide a repository of pathologic materials and information relating to neoplasms and related lesions in individuals with occupational or other environmental exposure to carcinogens. 4. To attempt to increase the awareness of pathologists and other practicing physicians of the high degree of probability that a majority of human cancers are induced by carcinogens in the environment and to encourage them to inquire about the occupation and other areas of the environment of patients with neoplasms.